A safety ski binding of the above-mentioned type is described approximately in Austrian Pat. No. 270, 467. In this conventional construction, the support part is designed in connection with or resting on each arm of the two toggle levers of the front jaw, wherein a spring acts onto the arms of the toggle levers, which is supported on the support part and the support part is provided at least with a guideway for receiving one of the arms of the toggle levers. To return the toggle lever, which is moved or rather swung out during a release operation and serves as a sole holder, and thus the one of the support part, a spring must be used. If a spring is not provided, then after a release operation has been performed, the ski binding must be moved by hand into the initial position, which operation is complicated and is no longer affordable in view of the requirements of today, which requirements are made with respect to comfort on safety ski bindings.
A front jaw with a spring-loaded support member for the two sole holders and for a hold-down means is for example known from Austrian Pat. No. 315,041 (corresponds to U.S. Pat. No. 3,822,071). In this conventional construction, both the two sole holders and also the hold-down means are controlled by one single support member, which is constructed as a rotary member, wherein in each case one of the lever arms engages a rotating groove of the rotary member. Due to the fact that the hold-down means opens simultaneously with one of the sole holders, the release of the ski boot occurs in the vertical direction already at the start of the release operation, namely within the elasticity limit, wherein a release is not to take place, when the forces which act from outside are reduced. Since the resulting force, which starts the release operation, mostly brings about a twisting fall, the sole region of the ski boot adjacent the tip of the ski boot, is removed from the ski, if the upwardly opening hold-down means permits such a movement. Due to this removal, it is possible for snow, ice or the like to penetrate during the started fall between the upper surface of the ski and the underside of the ski boot sole, which makes a satisfactory closing of the binding more difficult, possibly is even prevented, if the release operation is terminated within the elasticity range, and downhill skiing is to be continued.
A different known front jaw, in which the two sole holders which are constructed as two-armed levers are designed independently from the hold-down means, is described for example in the Austrian Pat. No. 326,013 (corresponding to U.S. Pat. No. 3,854,741). This hold-down means is held during a lateral release operation of the ski boot in its base or initial position, which causes the upper surface of the ski boot which is in the tip area to rub on the underside of the hold-down means. Such frictional forces are undesired.
It is furthermore known from Austrian Pat. No. 272,908 to use a so-called stop surface to support the tip of the ski boot. Said stop surface is, however, a part of the entire stop member, which can be pivoted about an axis which is positioned substantially perpendicularly with respect to the upper surface of the ski against a resilient ball lock. The two sole holders are thereby at the same time constructed as a hold-down means, so that a separate hold-down means, as was mentioned above, is missing in this front jaw. Therefore, one can take from this reference in relationship to the subject matter of the invention only the knowledge of a stop surface for the tip of the ski boot. A further development of a stop surface for the support of the ski boot sole in the tip region of the ski boot is described in German OS No. 22 54 522 (corresponding to U.S. Pat. No. 3,910,592) in a form which is adjustable in longitudinal direction of the ski. Also this structural part, which is identified as a stop and which is screwed as a screw into the center web of a ski-fixed support part, thus represents during a release operation an additional frictional surface for the sole of the ski boot.
The purpose of the invention is now to provide in a safety ski binding, in particular in a front jaw, of the type mentioned in the beginning a support which is improved with respect to the frictional characteristic for the ski boot sole which is provided in the tip region of the ski boot and also to simplify the automatic return of the hold-down means.
Due to the fact that a support part which is associated with the hold-down means and can be swung together with same is provided for supporting the sole of the ski boot which is provided in the tip region of the ski boot, the support part follows the direction of the release of the ski boot, so that the occurring frictional forces are reduced. The hold-down means is thereby inventively freely swingable by a spring force, so that the entire ski binding construction can be simply manufactured and also less expensively. Also wear appearance on a separate spring thus do no longer occur.
It is preferable if the support part is arranged in the position of use of the binding between the sole holders and with a spacing therebetween. With this measure, an undesired jamming of the support part with one or with both sole holders is prevented.
A further development consists in the support part being arranged on the pivot axis of the hold-down means.
A further construction consists in the support part being formed by two shafts arranged projecting from the underside of the hold-down means in direction of the base plate and being arranged both to one another and also in relationship to the two sole holders at a distance from each other. This construction can be designed in a simple manner by the shafts being screw bolts which are screwed into the underside of the hold-down means or pins which are inserted with a forced fit.
Furthermore it is preferable if the two shafts are connected for a pivotal movement through a limited range to the hold-down means and if one each shaft there is provided a holding support member with a curved surface, which holding support members prevent a working of the shaft into the ski boot sole. The size of the created frictional forces is additionally reduced by the curvature of the holding support member and the swingable support of the two shafts.
An additional measure to reduce the frictional forces consists in providing in a conventional manner an insert of a material which has a low frictional resistance, for example polytetrafluoroethylene (known under the trademark Teflon), on the support part or on the two holding supports.
All of the now-mentioned measures and characteristics are important for the invention.